324 citations · 1.3k across the 21 of their papers we have counts for
21 papers
Improving Short-Term Stability in Optical Lattice Clocks by Quantum Nondemolition Measurements
Daniel Benedicto Orenes, Robert J. Sewell, Jérôme Lodewyck +1
We propose a multimeasurement estimation protocol for Quantum Nondemolition (QND) measurements in a Rabi clock interferometer. The method is well suited for current state-of-the-ar…
Entanglement and extreme planar spin squeezing
Giuseppe Vitagliano, Giorgio Colangelo, Ferran Martin Ciurana +3
We introduce an entanglement-depth criterion optimized for planar quantum squeezed (PQS) states. It is connected with the sensitivity of such states for estimating an arbitrary, no…
Entanglement-enhanced phase estimation without prior phase information
G. Colangelo, F. Martin Ciurana, G. Puentes +2
We study the generation of planar quantum squeezed (PQS) states by quantum non-demolition (QND) measurement of a cold ensemble of Rb atoms. Precise calibration of the QND me…
Simultaneous tracking of spin angle and amplitude beyond classical limits
Giorgio Colangelo, Ferran Martin Ciurana, Lorena C. Bianchet +2
We show how simultaneous, back-action evading tracking of non-commuting observables can be achieved in a widely-used sensing technology, atomic interferometry. Using high-dynamic-r…
Entanglement-enhanced radio-frequency field detection and waveform sensing
F. Martin Ciurana, G. Colangelo, L. Slodicka +2
We demonstrate a new technique for detecting components of arbitrarily-shaped radio-frequency waveforms based on stroboscopic back-action evading measurements. We combine quantum n…
Real-time shot-noise-limited differential photodetection for atomic quantum control
F. Martin Ciurana, G. Colangelo, Robert J. Sewell +1
We demonstrate high-efficiency, shot-noise-limited differential photodetection with real-time signal conditioning, suitable for feedback-based quantum control of atomic systems. Th…
Quantum non-demolition measurement enables macroscopic Leggett-Garg tests
Costantino Budroni, Giuseppe Vitagliano, Giorgio Colangelo +4
We show how a test of macroscopic realism based on Leggett-Garg inequalities (LGIs) can be performed in a macroscopic system. Using a continuous-variable approach, we consider quan…
Generation of macroscopic singlet states in a cold atomic ensemble
N. Behbood, F. Martin Ciurana, G. Colangelo +4
We report the generation of a macroscopic singlet state in a cold atomic sample via quantum non-demolition (QND) measurement induced spin squeezing. We observe 3 dB of spin squeezi…
Ultrasensitive Atomic Spin Measurements with a Nonlinear Interferometer
R. J. Sewell, M. Napolitano, N. Behbood +3
We study nonlinear interferometry applied to a measurement of atomic spin and demonstrate a sensitivity that cannot be achieved by any linear-optical measurement with the same expe…
Feedback-cooling of an atomic spin ensemble
N. Behbood, M. Napolitano, G. Colangelo +4
We describe a measurement-and-feedback technique to deterministically prepare low-entropy states of atomic spin ensembles. Using quantum non-demolition measurement and incoherent o…
Quantum atom-light interfaces in the gaussian description for spin-1 systems
Giorgio Colangelo, Robert J. Sewell, Naeimeh Behbood +2
We extend the covariance-matrix description of atom--light quantum interfaces, originally developed for real and effective spin-1/2 atoms, to include "spin alignment" degrees of fr…
Real-time vector field tracking with a cold-atom magnetometer
Naeimeh Behbood, Ferran Martin Ciurana, Giorgio Colangelo +3
We demonstrate a fast three-axis optical magnetometer using cold, optically-trapped Rb gas as a sensor. By near-resonant Faraday rotation we record the free-induction decay…
Certified quantum non-demolition measurement of a macroscopic material system
R. J. Sewell, M. Napolitano, N. Behbood +2
Quantum non-demolition (QND) measurements improve sensitivity by evading measurement back-action. The technique was first proposed to detect mechanical oscillations in gravity wave…
Planar squeezing by quantum non-demolition measurement in cold atomic ensembles
Graciana Puentes, Giorgio Colangelo, Robert J. Sewell +1
Planar squeezed states, i.e. quantum states which are squeezed in two orthogonal spin components, have recently attracted attention due to their applications in atomic interferomet…
Quantum control of spin-correlations in ultracold lattice gases
P. Hauke, R. J. Sewell, M. W. Mitchell +1
We demonstrate that it is possible to prepare a lattice gas of ultracold atoms with a desired non-classical spin-correlation function using atom-light interaction of the kind routi…
Certified quantum non-demolition measurement of material systems
Morgan W. Mitchell, Marco Koschorreck, Marcin Kubasik +2
An extensive debate on quantum non-demolition (QND) measurement, reviewed in Grangier et al. [Nature, {\bf 396}, 537 (1998)], finds that true QND measurements must have both non-cl…
Efficient quantification of non-Gaussian spin distributions
B. Dubost, M. Koschorreck, M. Napolitano +3
We study theoretically and experimentally the quantification of non-Gaussian distributions via non-destructive measurements. Using the theory of cumulants, their unbiased estimator…
Magnetic sensitivity beyond the projection noise limit by spin squeezing
R. J. Sewell, M. Koschorreck, M. Napolitano +3
We report the generation of spin squeezing and entanglement in a magnetically-sensitive atomic ensemble, and entanglement-enhanced field measurements with this system. A maximal Ra…
Interaction-based quantum metrology showing scaling beyond the Heisenberg limit
M. Napolitano, M. Koschorreck, B. Dubost +3
Quantum metrology studies the use of entanglement and other quantum resources to improve precision measurement. An interferometer using N independent particles to measure a paramet…
Measuring Energy Differences by BEC Interferometry on a Chip
Florian Baumgartner, R. J. Sewell, S. Eriksson +4
We investigate the use of a Bose-Einstein condensate trapped on an atom chip for making interferometric measurements of small energy differences. We measure and explain the noise i…
Atom chip for BEC interferometry
R. J. Sewell, J. Dingjan, F. Baumgartner +8
We have fabricated and tested an atom chip that operates as a matter wave interferometer. In this communication we describe the fabrication of the chip by ion-beam milling of gold…